What Causes the Car's Exhaust Emission Warning Light to Illuminate?

[VonCharlotte]

Car's exhaust emission warning light illuminates due to the following reasons: 1. Sensor issues: When sensors such as water temperature, crankshaft position, air flow, intake temperature, or oxygen sensors are damaged, have poor contact, or experience signal interruption, the car's ECU cannot accurately obtain engine data; 2. Maintenance issues: Failure to perform regular maintenance and poor driving habits can increase the burden on the engine's operation; 3. Fuel quality issues: The fuel added to the car has specific ratings, and failure to add the required type can cause engine wear; 4. Poor combustion of the air-fuel mixture: This can lead to engine carbon deposits or knocking issues, which the engine's oxygen sensor will detect; 5. False faults: These can occur due to impacts during driving, tampering with certain engine connectors, or temporary signal interruptions in the ECU.